Particle Transport and Mesh Cell Size

siw · March 22, 2012, 07:01

Hi,

For an incompressible flow with particle tracking is there guidelines on how small mesh cells should be?

For example: should a mesh be sized so that a particle is expected to move cross a cell face per time step? Or perhaps move every 2nd timestep?

Thanks

doronzo · March 22, 2012, 08:58

hi

it probably depends on the particle properties, e.g. dimension, velocity. for example, very small and slow particles would need a highly refined mesh, of the order of the particles themselves, to ensure they can move at least in one cell/time step, but this would probably mean to use a four-way coupling between the fluid and the particles (solving for the turbulence of wakes around the particles), which isn't allowed in the DPM point-particle tracking (where the particle volume fraction is neglected).

on the other hand, a highly refined mesh would allow the Fluent particles, which are cluster of particles, to represent a more realistic mass of actual particles

regards

March 22, 2012, 07:01	Particle Transport and Mesh Cell Size	#1
siw Senior Member Stuart Join Date: Jul 2009 Location: Portsmouth, England Posts: 739 Rep Power: 26	Hi, For an incompressible flow with particle tracking is there guidelines on how small mesh cells should be? For example: should a mesh be sized so that a particle is expected to move cross a cell face per time step? Or perhaps move every 2nd timestep? Thanks

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March 22, 2012, 08:58		#2
doronzo Member Domenico Join Date: Sep 2011 Location: Atlanta Posts: 39 Rep Power: 15	hi it probably depends on the particle properties, e.g. dimension, velocity. for example, very small and slow particles would need a highly refined mesh, of the order of the particles themselves, to ensure they can move at least in one cell/time step, but this would probably mean to use a four-way coupling between the fluid and the particles (solving for the turbulence of wakes around the particles), which isn't allowed in the DPM point-particle tracking (where the particle volume fraction is neglected). on the other hand, a highly refined mesh would allow the Fluent particles, which are cluster of particles, to represent a more realistic mass of actual particles regards